You can check Prof. Eshashi paper in JMEMS. He has shown the pyrex glass
etching by DRIE ..i thik aspect ratio is abt 4. You can also check Ciprian
Illiescu's paper in 'surface and coating' on wet etching of glass.

Thanks,
Pradeep


On 3/22/07, Gao Xiaotong  wrote:
>
> Dear all,
> I plan to etch penetrating holes on glass substrate. But I am worrying
> about the aspect ratio. Could anybody give me some ideas about high aspect
> ration glass etching?